# input
time = input().split(':')
hour = int(time[0])
minute = int(time[1])

# process
if minute < 55 :
    minute += 5
    if hour < 10 :
        print("0{0}:{1}".format(str(hour),str(minute)))
    else:
        print("{0}:{1}".format(str(hour),str(minute)))
        
else: #minuteが更新し、hourが1繰り上がる
    hour += 1
    minute = minute+5 -60
    if hour < 24:
        if hour < 10:
            print("0{0}:0{1}".format(str(hour),str(minute)))    
        else:
            print("{0}:0{1}".format(str(hour),str(minute)))
    else:
        print("00:0{0}".format(str(minute)))